No query window is displayed in the Tracker navigator, only the search buttons on top and a message that says:
Unable to create view: An unexpected exception was thrown.

Details:

java.lang.NullPointerException at org.eclipse.search2.internal.ui.InternalSearchUI.activateSearchView(InternalSearchUI.java:263) at org.eclipse.search.ui.NewSearchUI.activateSearchResultView(NewSearchUI.java:40) at com.polarion.tracker.internal.ui.f.a(f.java:70) at com.polarion.tracker.internal.ui.navigator.j.a(j.java:521) at com.polarion.tracker.internal.ui.navigator.j.createPartControl(j.java:245) at org.eclipse.ui.internal.ViewReference.createPartHelper(ViewReference.java:305)